<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Title</title>
    
    <style>
      body { /*删除浏览器自带样式*/
        margin: 0px;
      }
    </style>
  </head>
  
  <body>
    <!-- ====================== 块级元素：独占一行 ====================== -->
    <!-- 标题<h1><h2><h3><h4><h5><h6> -->
    <h1>标题一</h1>
    <h2>标题二</h2>
    <h3>标题三</h3><h4>标题四</h4><h5>标题五</h5><h6>标题六</h6>
    <hr><!-- 分隔符 -->
    
    <!-- 标题组<hgroup> -->
    <hgroup>
      <h1>标题分组1-标题一</h1>
      <h2>标题分组1-标题二</h2>
    </hgroup>
    <hgroup>
      <h1>标题分组2-标题一</h1>
      <h2>标题分组2-标题二</h2>
    </hgroup>
    <hr>
    
    <!-- 段落<p> -->
    <p>段落</p>
    <p>段落</p>
    <hr>
    
    <!-- 块引用<blockquote> -->
    <blockquote cite="来源">
      块引用
    </blockquote>
    <hr>
    <hr>
    
    
    <!-- ====================== 内联元素：不独占一行 ====================== -->
    <!-- 行内引用<q> -->
    <q>行内引用</q>哈哈
    
    <!-- 换行<br/> -->
    <br/>
    
    <!-- 强调<em> -->
    <em>强调</em>哈哈<br/>
    
    <!-- 斜体<i> -->
    <i>斜体</i>哈哈<br/>
    
    <!-- 重要<strong> -->
    <strong>重要</strong>哈哈<br/>
    
    <!-- 加粗<b> -->
    <b>加粗</b><br/>
    
    <!-- 下划线<u> -->
    <u>下划线</u><br/>
  
  </body>

</html>